1. Field of the Invention
The present invention relates to a method for programmed automatic exposure control and a device thereof and, more particularly, to improvements on the method and device for the exposure control wherein an iris is opened so that an aperture area grows from a small size to a large size and an aperture closing operation is made on the half way of an opening operation due to a signal from a photometry means.
2. Description of the Prior Art
The conventional method for automatic exposure control as stated above has been one wherein an aperture of the shuttercum-iris (hereinafter merely referred to as a shutter) opens continuously and closes when a signal is outputted from a photometry means. Generally, the shutter speed varies by the equivalent of 0.5 EV and the iris varies by the equivalent of 0.5 EV with the .gamma. value of CdS photoelectric element in the photometry circuit that is 0.5 when the amount of the light of incidence from the subject varies by 1 EV. Therefore, it has been impossible to photograph laying stress on the iris effect even when the bright subject is photographed. Namely, even when the light amount is LV 13 for ASA 100, the F/T is in the range of 5.6/250-8/125. Since it is impossible to photograph laying stress on the iris effect, it has been the method wherein a high accuracy for the focus adjustment is required.